JP7708103B2 - Nozzle plate, inkjet head, method of manufacturing a nozzle plate, and method of manufacturing an inkjet head - Google Patents

Description

The present invention relates to a nozzle plate, an inkjet head, a method for manufacturing a nozzle plate, and a method for manufacturing an inkjet head.

Inkjet heads that eject ink have nozzles formed on a nozzle plate, which is a substrate on which a flow path substrate is bonded with an adhesive, and eject ink from the nozzles. A method for forming nozzles in a substrate is known in which a tool is pressed into the substrate, a drawing process is performed so that the concave portion reaches the rear surface of the substrate, and then the convex portion on the rear surface of the substrate is polished to transfer the shape of the tool so that it penetrates the substrate (see, for example, Patent Document 1).

Metals such as SUS (Steel Use Stainless) are used as the base material for such nozzle plates, from the viewpoints of chemical stability against ink and durability against mechanical friction. Known methods for processing the outer shape of a nozzle plate from a metal plate in which nozzles are formed include, for example, wet etching using an etching solution (see Patent Document 2) and laser etching using a laser device (see Patent Document 3).

Patent No. 3755332 JP 2019-217706 A JP 2007-307842 A

However, when performing the contour processing using wet etching, the resist mask may get inside the nozzle, and even if the resist is removed after the contour processing, there is a risk that resist residue may remain inside the nozzle.

Furthermore, when performing external processing by laser etching, there is a risk of poor adhesion or voids occurring due to protrusions caused by dross near the laser processing location. The generation of dross can be suppressed by using a short-pulse laser such as a picosecond or femtosecond laser, but this is less economical because the equipment is more expensive than the commonly used nanosecond pulse lasers.

In addition, when bonding the flow path substrate to the nozzle plate, there is a risk of poor adhesion occurring, with the adhesive spilling out onto the sides.

The present invention has been made in consideration of these circumstances, and its object is to provide a nozzle plate, an inkjet head, a method for manufacturing a nozzle plate, and a method for manufacturing an inkjet head that can suppress the occurrence of poor adhesion or voids during bonding.

In order to solve the above problems, the present invention provides a nozzle plate for an inkjet head, comprising:
The nozzle plate has a first surface bonded to an upper substrate by an adhesive;
a second surface provided with nozzle openings for ejecting ink;
The first surface has a step portion formed on an edge portion ,
The second surface has a planar edge .

The invention described in claim 2 is the nozzle plate described in claim 1,
Dross is formed on the step portion.

The invention according to claim 3 is the nozzle plate according to claim 1 or 2,
The substrate forming the nozzle plate is made of silicon or metal.

The invention according to claim 4 is the nozzle plate according to any one of claims 1 to 3,
The step portion has a depth of 5 μm to 10 μm in the direction toward the center of the nozzle plate.

The present invention as set forth in claim 5 is an inkjet head, comprising:
The nozzle plate according to claim 1 .

The present invention according to claim 6 provides a method for manufacturing the nozzle plate according to any one of claims 1 to 4, comprising the steps of:
a groove processing step of forming recesses only on a first surface of a single substrate so as to form the outlines of a plurality of nozzle plates;
a nozzle forming step of forming a nozzle so that an opening is formed on the second surface of the base material;
and an outer shape processing step of cutting the recess by laser processing to cut out the nozzle plate from the base material.

The invention described in claim 7 is a method for manufacturing a nozzle plate according to claim 6, comprising the steps of:
The recess is formed by wet etching.

The invention according to claim 8 provides a method for manufacturing a nozzle plate according to claim 6 or 7, comprising the steps of:
A water-repellent film forming step is provided for forming a water-repellent film on the second surface.

The present invention according to claim 9 is a method for manufacturing an inkjet head, comprising the steps of:
A nozzle plate manufacturing process for manufacturing the nozzle plate according to any one of claims 1 to 4;
a bonding step of bonding a first surface of the nozzle plate and an upper substrate with an adhesive;
has.

The nozzle plate, inkjet head equipped with the nozzle plate, method for manufacturing the nozzle plate, and method for manufacturing the inkjet head of the present invention can suppress the occurrence of poor adhesion or voids during bonding.

1 is an overall view of an inkjet head according to an embodiment of the present invention. FIG. 1B is a cross-sectional view taken along line IB-IB of FIG. FIG. 2 is an enlarged cross-sectional view of a nozzle plate according to the embodiment. 5 is a flowchart showing a method of manufacturing a nozzle plate according to the embodiment. 3A to 3C are a top view and a cross-sectional view taken along line AB showing a method for manufacturing a nozzle plate according to the embodiment. 3A to 3C are a top view and a cross-sectional view taken along line AB showing a method for manufacturing a nozzle plate according to the embodiment. 3A to 3C are a top view and a cross-sectional view taken along line AB showing a method for manufacturing a nozzle plate according to the embodiment. 3A to 3C are a top view and a cross-sectional view taken along line AB showing a method for manufacturing a nozzle plate according to the embodiment.

Below, embodiments of the nozzle plate, inkjet head equipped with a nozzle plate, a method for manufacturing a nozzle plate, and a method for manufacturing an inkjet head of the present invention are described with reference to the drawings.

Fig. 1A is an overall view of the inkjet head 1 according to this embodiment, and Fig. 1B is a cross-sectional view taken along line IB-IB of Fig. 1A as viewed from the side (-X direction side) of the inkjet head 1. Fig. 1B shows a cross section of the inkjet head 1 on a plane including four nozzles 14 included in four nozzle rows.
The inkjet head 1 includes a head chip 2, a common ink chamber 70, a support substrate 80, wiring members 3, a drive unit 4, and the like.

The head chip 2 is configured to eject ink from the nozzles 14, and is formed by stacking multiple (four in this example) plate-shaped substrates. The lowest substrate in the head chip 2 is the nozzle plate 10. Multiple nozzles 14 are formed in the nozzle plate 10, and ink can be ejected approximately perpendicular to the ink ejection surface (exposed surface of the nozzle plate 10) on which the openings of the nozzles 14 are provided. On the opposite side of the ink ejection surface of the nozzle plate 10, a pressure chamber substrate 20 (chamber plate), a spacer substrate 40, and a wiring substrate 50 are laminated and bonded with adhesive or the like in order toward the upper side (+Z direction). Hereinafter, the nozzle plate 10, the pressure chamber substrate 20, the spacer substrate 40, and the wiring substrate 50 will be referred to individually or collectively as the flow path substrates 10, 20, 40, 50, etc.

These flow path substrates 10, 20, 40, and 50 are provided with ink flow paths that communicate with the nozzles 14, and are opened on the exposed side (+Z direction side) of the wiring substrate 50. A common ink chamber 70 is provided on the exposed surface of the wiring substrate 50 so as to cover all the openings. The common ink chamber 70 has an ink supply section 70a that supplies ink to the ink chamber forming member 70c, and an ink discharge section 70b that discharges ink from the ink chamber forming member 70c, both provided at the top. The ink stored in the ink chamber forming member 70c of the common ink chamber 70 is supplied to each nozzle 14 from the opening of the wiring substrate 50.

A pressure chamber 21 is provided in the middle of the ink flow path. The pressure chamber 21 is provided penetrating the pressure chamber substrate 20 in the vertical direction (Z direction), and the upper surface of the pressure chamber 21 is formed by a vibration plate 30 provided between the pressure chamber substrate 20 and the spacer substrate 40. A pressure change is applied to the ink in the pressure chamber 21 by the vibration plate 30 (pressure chamber 21) being deformed by the displacement (deformation) of the piezoelectric element 60 in the storage section 41 provided adjacent to the pressure chamber 21 via the vibration plate 30. By applying an appropriate pressure change to the ink in the pressure chamber 21, the ink in the ink flow path is ejected as droplets from the nozzle 14 communicating with the pressure chamber 21.

The support substrate 80 is bonded to the upper surface of the head chip 2 and holds the ink chamber forming member 70c of the common ink chamber 70. The support substrate 80 has an opening of approximately the same size and shape as the opening on the lower surface of the ink chamber forming member 70c, and the ink in the common ink chamber 70 is supplied to the upper surface of the head chip 2 through the opening on the lower surface of the ink chamber forming member 70c and the opening in the support substrate 80.

The wiring member 3 is, for example, an FPC (Flexible Printed Circuits) and is connected to the wiring of the wiring board 50. The piezoelectric element 60 is displaced by a drive signal transmitted to the wiring 51 and the connection part 52 (conductive member) in the storage part 41 via this wiring. The wiring member 3 is pulled out through the support board 80 and connected to the drive part 4.

The drive unit 4 receives control signals from the control unit of the inkjet recording device, power supply from the power supply unit, etc., and outputs appropriate drive signals for the piezoelectric elements 60 to the wiring member 3 in accordance with the ink ejection or non-ejection operation from each nozzle 14. The drive unit 4 is composed of an IC (Integrated Circuit) etc.

Figure 2 is a cross-sectional view showing the configuration of the nozzle plate 10. In Figure 2, an enlarged cross-section of the nozzle plate 10 is shown.

The nozzle plate 10 has a substrate 11 cut out from a base material and provided with nozzles 14, a protective film 12 provided on the plate surface of the substrate 11 and the inner wall surfaces of the nozzles 14, a water-repellent film 13 formed on the underside of the substrate 11 by overlapping the protective film 12, a step portion 151 which is a notch provided in the edge portion, and glue guards 16 provided on both sides of each nozzle 14.
In the following description, the upper surface of the substrate 11 will be referred to as a first surface 11a, and the lower surface of the substrate 11 will be referred to as a second surface 11b.

The substrate 11 is a plate-shaped member cut out from a base material such as SUS (Steel Use Stainless) having a thickness of about 25 μm to 300 μm. By using SUS as the base material, it is possible to form a nozzle plate 10 that has excellent chemical stability against ink and mechanical friction durability. As described later, when a silicon substrate is used as the substrate 11, a thermal oxide film may be formed on the outer layer of the substrate 11.

The nozzle 14 is a cylindrical hole having a circular opening on the second surface 11 b of the substrate 11 .
The diameter of the opening of the nozzle 14 can be about 15 μm to 30 μm.

_The protective film 12 can be made of a material that does not dissolve when it comes into contact with ink, such as silicon carbide (SiC), silicon oxide carbide (SiOC), and silicon oxide ( _SiO2 ), as well as metal oxide films such as _aluminum oxide ( _Al2O3 ), zirconium oxide ( _ZrO2 ), titanium oxide ( _TiO2 ), hafnium oxide ( _HfO2 ), and tantalum oxide ( _Ta2O3 ), and metal silicate films that contain silicon in metal oxide films (such as tantalum silicate (TaSiO)).
The thickness of the protective film 12 is not particularly limited, but is preferably about 50 nm to 500 nm, for example.

The protective film 12 made of such an ink-resistant material prevents the substrate 11 from being corroded by ink (especially alkaline ink or acidic ink). The protective film 12 may also be used as a base film for the water-repellent film 13 described below. The ink-resistant protective film 12 is unlikely to peel off even when it comes into contact with ink, so by using the protective film 12 as a base film, it is possible to prevent the water-repellent film 13 from peeling off together with the protective film 12 as a base film.

The water-repellent film 13 is formed on the protective film 12, and its surface forms the ink ejection surface. The water-repellent film 13 is a layer provided to provide water repellency to ink and to suppress adhesion of ink and foreign matter. The water-repellent film 13 is formed by depositing a silane coupling agent having a perfluorooxyl group on the protective film 12 made of the material described above as a base film.
Furthermore, the water-repellent film 13 has an opening penetrating the water-repellent film 13 at the position where the nozzle 14 is formed, and the ink discharged from the nozzle 14 is ejected from this opening.

The step portion 151 is a cutout provided along the outer periphery of the first surface 11a, and dross 152 generated by laser processing described later is placed on the edge portion. The step portion 151 is a space that prevents the dross 152 generated when performing contour processing on the recess 15 of the nozzle plate 10 from impeding the adhesion between the nozzle plate 10 and the flow path substrate 20. The step portion 151 also serves as a space to accommodate adhesive that protrudes from the end face of the nozzle plate 10 when the nozzle plate 10 and the flow path substrate 20 are adhered to each other.
The depth of the step 151 is not particularly limited, but is preferably 5 μm to 10 μm.

The glue guards 16 are recessed grooves provided so as to be approximately parallel to the row in which the nozzles 14 are formed. By providing the glue guards 16, it is possible to reduce the risk of excess adhesive entering the nozzles 14 when the nozzle plate 10 is bonded to the pressure chamber substrate 20, which is the upper substrate, with an adhesive.
In FIG. 2, one glue guard 16 is provided on each side of the nozzle 14, but the positions and number of the glue guards 16 are not limited to this.

Next, a method for manufacturing the inkjet head 1 of this embodiment will be described, focusing on a method for manufacturing the nozzle plate 10.
Fig. 3 is a flow chart showing the procedure of a process (nozzle plate manufacturing process) for manufacturing the nozzle plate 10. Also, Fig. 4A to Fig. 4D are a top view and a cross-sectional view taken along line AB for explaining the nozzle plate manufacturing process.
As shown in FIGS. 4A to 4D, the nozzle plate manufacturing process according to this embodiment makes it possible to simultaneously manufacture a plurality of nozzle plates 10 from a single substrate.

In the nozzle plate manufacturing process, first, as shown in FIG. 4A, a groove (half etching) is performed by wet etching on the portion of the first surface 11a of the substrate 11 that will be contoured in the subsequent step S106, thereby forming a recess 15 (step S101).

The wet etching process can be performed by forming a resist mask on the substrate 11 except for the portion where the groove is to be processed, and immersing the substrate 11 in an etching solution. The resist mask can be made of an inorganic material such as silicon, as long as it can protect the substrate 11 against the etching solution. In addition, when the substrate 11 is a SUS base material, a neutral salt etching solution, which is an aqueous solution containing ferric chloride (FeCl ₂ ) or cupric chloride (CuCl ₂ ), is generally used as the etching solution. In addition, when the substrate 11 is a silicon substrate, a mixture of nitric acid (HNO ₃ ) and hydrofluoric acid (HF) is generally used. However, the etching solution is not limited to this, and any known etching solution can be selected.
After the wet etching process, the resist mask is removed from the surface of the substrate 11 .

In addition, during the groove processing process, a groove guard 16, which is a concave groove portion parallel to the row in which the nozzles 14 are formed, is simultaneously formed.

Next, as shown in FIG. 4B, punching is performed on the substrate 11 to form the nozzle 14 (step S102).

For the punching process, a tool is used to press the substrate 11. Specifically, one surface of the tool on which the nozzle forming portion is provided is opposed to the first surface 11a of the substrate 11, and the nozzle forming portion is pressed against the first surface 11a to perform pressing. As a result, a nozzle recess that is recessed toward the second surface 11b is formed on the first surface 11a, and a nozzle protrusion is formed on the second surface 11b.

Next, the nozzle protrusions protruding from the second surface 11b are polished and removed (step S103), whereby the nozzles 14 are opened on the second surface 11b.
As a result, a nozzle 14 is formed in the substrate 11, penetrating from the first surface 11a to the second surface 11b.

Next, a protective film 12 is formed on the nozzle plate 10, and a water-repellent film 13 is formed on the second surface 11b, which is the ink ejection surface (step S104).

First, the surface of the substrate 11 is cleaned to remove any foreign matter adhering to the substrate 11. The method for cleaning the substrate 11 can be, for example, US cleaning.

After cleaning the substrate 11, an ion bombardment process is performed on the surface of the substrate 11. The ion bombardment process is a process in which ions are collided with a member to be treated in a reduced pressure environment, thereby exerting a physical effect on the member to be treated.
Such an ion bombardment process removes impurities and a thin oxide film adhering to the surface of the substrate 11, cleaning the surface and improving the adhesion of the protective film 12. In addition, oxidation of the surface of the substrate 11 is suppressed.

After the ion bombardment process, a protective film 12 is formed on the surface of the substrate 11 by plasma CVD, and the substrate 11 on which the protective film 12 is formed is cleaned to remove foreign matter adhering to the protective film 12. The method for cleaning the protective film 12 can be US cleaning, as described above.

After cleaning the protective film 12, as shown in FIG. 4C, a water-repellent film 13 is formed on the protective film 12. The water-repellent film 13 is formed by a dry process, typically a vacuum deposition method, using a silane coupling agent having a perfluorooxyl group. As the silane coupling agent, aminosilane coupling agents such as γ-aminopropyltriethoxysilane, N-β-aminoethyl-γ-aminopropyltriethoxysilane, N-β-aminoethyl-γ-aminopropyltrimethoxysilane, N-β-aminoethyl-γ-aminopropylmethyldimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, and γ-ureidopropyltriethoxysilane, and epoxysilane coupling agents such as γ-glycidoxypropyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and γ-glycidoxypropylmethyldiethoxysilane can be used.
It should be noted that the method for forming the water-repellent film 13 is not limited to the above, and the film may be formed based on conventionally known components and methods, such as by immersing the substrate 11 in a solution in which a fluorine-containing organosilicon compound is diluted with a fluorine-based solvent, and then thermally drying the solution.

Next, the water-repellent film 13 formed on the surface other than the second surface 11b is removed (step S105). Specifically, the second surface 11b is first masked with polyimide tape, and the substrate 11 is placed in an ashing device and exposed to _O2 plasma for several tens of seconds to remove the water-repellent film 13 formed on the surface other than the second surface 11b. Thereafter, the polyimide tape is removed and the substrate is washed.
By the above method, the protective film 12 is formed on the entire surface of the substrate 11, and the water-repellent film 13 is formed only on the second surface 11b.

Next, as shown in FIG. 4D, the exterior shape of the substrate 11 is processed by laser processing (exterior shape processing process, step S106).

In the external processing step, a laser is used to cut the recess 15 along the recess 15 of the substrate 11, which was grooved in the previous step S101, to cut the nozzle plate 10 from the base material. As the laser light generated by the laser device, for example, an excimer laser light can be preferably exemplified. This is because the excimer laser light has a short wavelength and allows for preferable fine processing. The wavelength of the excimer laser light is in the range of 190 nm to 355 nm, and specific examples thereof include ArF (wavelength 193 nm), KrF (248 nm), XeCl (wavelength 308 nm), and XeF (wavelength 351 nm). Note that the laser light may be a conventionally known laser, such as a YAG laser or a _CO2 laser.

Since the laser processing in this step is performed by cutting the recess 15 of the nozzle plate 10 as described above, a step portion 151 as shown in FIG. 2 is formed on the edge of the nozzle plate 10 after the outer shape processing step.
Furthermore, normally, when the outer shape of the SUS substrate 11 is processed by laser processing, dross 152 is formed in the vicinity of the processed portion. However, in the present invention, since the laser processing is performed along the recess 15, dross 152 is formed on the edge of the step portion 151 as shown in FIG. 2.

By the above method, a nozzle plate 10 is obtained in which a step portion 151 with dross 152 attached is formed on the edge of the substrate 11. The nozzle plate 10 is laminated with the flow path substrates 20, 40, and 50 to manufacture the head chip 2, which is then combined with the common ink chamber 70, support substrate 80, wiring member 3, drive unit 4, etc., and assembled into a specified exterior member to complete the inkjet head 1.

Next, we will explain the experiments conducted to confirm the height of the dross formed during the external processing of the above embodiment.

In this experiment, the height of dross 152 formed when SUS was laser processed was evaluated.
Specifically, a SUS304HTA material having a thickness of 50 μm was used as a substrate, and 20 scans were performed for each level of laser output (2.4 W/1.8 W/1.2 W/0.6 W) and the presence or absence of assist gas were changed using MD-U1000C (manufactured by Keyence Corporation, wavelength: 355 nm, pulse width: 14 nsec, switch: 40 kHz, scan speed: 200 mm/sec) which is a solid-state laser device using YVO4 crystal. Next, after 20 minutes of US cleaning with pure water using 40 kHz ultrasonic waves, the height of the dross 152 generated near the processed part was measured using a laser microscope VK-X250 (manufactured by Keyence Corporation), and the average value was calculated.
Table I shows the results of this experiment.

As shown in levels 1-3 of Table 1, the height of the dross 152 can be reduced by decreasing the laser output. However, as shown in levels 4 and 8, reducing the output to 0.6 W or less is not preferable because it becomes impossible to perform external processing.
Furthermore, as shown in level 5-7, by using an assist gas, the change in height of the dross 152 due to the change in the laser output can be reduced, and the height becomes stable at 5 μm or less.
As shown in Experiment 1, the height of the dross 152 generated during laser processing is about 5 μm, and particularly 10 μm or less, so if the step portion 151 has a depth of about 5 μm, the dross 152 is less likely to cause poor adhesion or the generation of voids when bonding to the pressure chamber substrate 20. Furthermore, if the step portion 151 has a depth of about 10 μm, it is possible to prevent the dross 152 from interfering with adhesion after external processing, regardless of the conditions during laser processing.

As described above, the manufacturing method of the nozzle plate 10 according to the above embodiment includes at least a groove processing step in which grooves are processed by wet etching in the portion to be processed, thereby forming a plurality of recesses 15 in a single substrate, a nozzle forming step in which a plurality of nozzles 14 are formed by punching and polishing, and a contour processing step in which the contours of the plurality of nozzle plates 10 are processed along the recesses 15 by laser processing.
According to this method, the dross 152 produced by the contour processing process occurs in the step portion 151 formed by the groove processing process, so that when the nozzle plate 10 is bonded to the pressure chamber substrate 20, defects such as poor adhesion and the occurrence of voids can be suppressed.

In addition, in the manufacturing method of the nozzle plate 10 according to the above embodiment, there is no need to remove the dross 152 that occurs on the edge of the nozzle plate 10 by polishing in order to suppress the occurrence of the above-mentioned defects. Therefore, the nozzle plate 10 can be manufactured efficiently, and the productivity is excellent.

In addition, in the manufacturing method of the nozzle plate 10 according to the above embodiment, as shown in Fig. 4, each processing step can be performed to manufacture multiple nozzle plates 10 from a single substrate 11. Therefore, multiple nozzle plates 10 can be manufactured efficiently, resulting in excellent productivity.

In addition, in the manufacturing method of the nozzle plate 10 according to the above embodiment, the outer shape is processed by laser processing, which eliminates the need for processes such as forming and removing a resist mask, as compared to when the outer shape is processed by wet etching, and no resist residue is generated inside the nozzle 14. Therefore, the nozzle plate 10 can be manufactured efficiently, resulting in excellent productivity.

In addition, in the manufacturing method of the nozzle plate 10 according to the above embodiment, even if dross 152 is generated during the external processing step, the occurrence of the above-mentioned defects can be suppressed. Therefore, there is no need to use a short-pulse laser device with a pulse width on the order of picoseconds or femtoseconds, and the nozzle plate 10 can be provided at a low cost.

In addition, since the nozzle plate 10 manufactured by the manufacturing method according to the above embodiment has dross 152 generated in the step portion 151, when the nozzle plate 10 is bonded to the upper substrate, the pressure chamber substrate 20, with adhesive, the dross 152 can be prevented from forming a wall and spilling out onto the side, even if a large amount of adhesive is used.

Furthermore, by using the nozzle plate 10 manufactured by the manufacturing method according to the above embodiment, the inkjet head 1 can be manufactured cheaply and efficiently, resulting in excellent productivity.

The present invention is not limited to the above-described embodiment, and various modifications are possible.
For example, in the above embodiment, the base material of the nozzle plate 10 is made of SUS, but this is not limited to this, and any conventionally known material, such as a silicon substrate or an electroformed metal such as Ni, may also be used.

In addition, in the above embodiment, an example has been described in which the protective film 12 is formed over the entire surface of the substrate 11, but this is not limited thereto, and the protective film 12 may be provided on at least a portion of the surface of the substrate 11, including the first surface 11a and the inner wall surface of the nozzle 14 (i.e., any area that may come into contact with ink and that needs to be ink-resistant).

In addition, the protective film 12 has a single-layer structure, but the configuration of the protective film 12 is not limited to this and may have a multi-layer structure. In addition, if the protective film 12 is not required, the protective film 12 does not have to be provided on the nozzle plate 10.

In addition, the inner wall surface of the nozzle 14 may be tapered so that the cross-sectional area parallel to the first surface 11a becomes smaller as it approaches the opening of the nozzle 14.

In addition, the nozzle 14 provided in the nozzle plate 10 may be configured to include a communication passage having an opening wider than the nozzle 14, an ink flow path for guiding ink that is not ejected from the nozzle 14, or the like. The shape of the nozzle 14 is not limited to the approximately truncated cone shape shown in FIG. 2.

In addition, in cases where there is no need to impart water repellency to the ink ejection surface of the inkjet head 1, it is not necessary to provide a water-repellent film 13 on the nozzle plate 10.

In the above embodiment, the vent mode inkjet head 1 is described as an example in which the pressure of the ink in the pressure chamber 21 is changed by deforming the piezoelectric element 60 to eject the ink, but the present invention is not limited to this. For example, the present invention may be applied to a shear mode inkjet head in which a pressure chamber is provided inside the piezoelectric body and a shear mode type displacement is caused in the piezoelectric body on the wall surface of the pressure chamber to change the pressure of the ink in the pressure chamber. Furthermore, the present invention is not limited to the method of deforming the pressure chamber, and may be applied to, for example, a thermal type inkjet head in which ink is ejected by generating bubbles in the ink by heating.

In the above embodiment, the recess 15 is formed by wet etching in the groove processing step, but this is not limited to this and it may be formed by laser processing. However, since laser processing may cause distortion and warping of the base material, it is preferable to form it by wet etching.

Although several embodiments of the present invention have been described, the scope of the present invention is not limited to the above-described embodiments, but includes the scope of the invention described in the claims and their equivalents.

The present invention can be used in nozzle plates to prevent poor adhesion or the occurrence of voids during bonding.

1 Inkjet head 10 Nozzle plate 11a First surface 11b Second surface 13 Water-repellent film 14 Nozzle 15 Recess 20 Pressure chamber substrate (upper substrate)
151 Step portion 152 Dross

Claims (9)

A nozzle plate of an inkjet head,
The nozzle plate has a first surface bonded to an upper substrate by an adhesive;
a second surface provided with nozzle openings for ejecting ink;
The first surface has a step portion formed on an edge portion ,
The second surface is a nozzle plate having a planar edge . The nozzle plate according to claim 1 , wherein dross is formed on the step portion. The nozzle plate according to claim 1 or 2, wherein the substrate forming the nozzle plate is silicon or metal. The nozzle plate according to any one of claims 1 to 3, wherein the step portion has a depth of 5 μm or more and 10 μm or less in the direction toward the center of the nozzle plate. An inkjet head comprising a nozzle plate according to any one of claims 1 to 4. A method for manufacturing the nozzle plate according to any one of claims 1 to 4, comprising the steps of:
a groove processing step of forming recesses only on a first surface of a single substrate so as to form the outlines of a plurality of nozzle plates;
a nozzle forming step of forming a nozzle so that an opening is formed on the second surface of the base material;
and an outline processing step of cutting the recess by laser processing to cut out the nozzle plate from the base material. The method for manufacturing a nozzle plate according to claim 6, wherein the recess is formed by wet etching. The method for manufacturing a nozzle plate according to claim 6 or 7, further comprising a water-repellent film forming step for forming a water-repellent film on the second surface. A nozzle plate manufacturing process for manufacturing the nozzle plate according to any one of claims 1 to 4;
a bonding step of bonding a first surface of the nozzle plate and an upper substrate with an adhesive;
A method for manufacturing an inkjet head having the above structure.